Your heart is a muscle about the size of your fist. This muscle pumps nonstop to keep your body supplied with blood that is rich in oxygen. To do its job, your heart needs its own oxygen-rich blood supply. Blood gets oxygen from the lungs and travels to your heart through the coronary arteries.

Normal Coronary Arteries Carry Blood

A large vessel called the aorta carries blood from your heart to the rest of your body The coronary arteries branch off from the aorta. Smaller arteries branch off from the coronary arteries. These smaller arteries run over and through the heart muscle. They nourish every part of the heart with blood.